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[RFC,2/7] error reporting: Provide error_report_errno (and error_vreport_errno)

Message ID 1524761612-5307-3-git-send-email-ian.jackson@eu.citrix.com
State New
Headers show
Series Introduce error_[v]report_errno[val] | expand

Commit Message

Ian Jackson April 26, 2018, 4:53 p.m. UTC 
This will let us replace a lot of open coded calls to perror,
strerror, etc.

No callers yet so no functional change.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
---
 include/qemu/error-report.h |  2 ++
 util/qemu-error.c           | 28 ++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

Comments

Eric Blake April 26, 2018, 5:27 p.m. UTC | #1 
On 04/26/2018 11:53 AM, Ian Jackson wrote:
> This will let us replace a lot of open coded calls to perror,
> strerror, etc.
> 
> No callers yet so no functional change.
> 
> Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
> ---
>  include/qemu/error-report.h |  2 ++
>  util/qemu-error.c           | 28 ++++++++++++++++++++++++++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
> index e1c8ae1..2b29678 100644
> --- a/include/qemu/error-report.h
> +++ b/include/qemu/error-report.h
> @@ -37,10 +37,12 @@ void error_printf_unless_qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
>  void error_set_progname(const char *argv0);
>  
>  void error_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
> +void error_vreport_errno(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);

I'd rather us ALWAYS require an explicit argument for the error value,
rather than reading errno.  That way, it's easier to audit that the
caller is passing in a known error value, rather than checking if errno
has been inadvertently changed during intermediate code between when the
error was detected and when the message is generated.  Furthermore, this
is inconsistent with the existing error_setg_errno().

Thus, I do not think we want this function.  Your addition in 5/7 is
better, but a rather verbose name, so I think THAT addition deserves to
be named error_vreport_errno.
diff mbox series

Patch

diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
index e1c8ae1..2b29678 100644
--- a/include/qemu/error-report.h
+++ b/include/qemu/error-report.h
@@ -37,10 +37,12 @@  void error_printf_unless_qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 void error_set_progname(const char *argv0);
 
 void error_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
+void error_vreport_errno(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
 void warn_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
 void info_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
 
 void error_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
+void error_report_errno(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 void warn_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 void info_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 
diff --git a/util/qemu-error.c b/util/qemu-error.c
index 9acc4b5..428c762 100644
--- a/util/qemu-error.c
+++ b/util/qemu-error.c
@@ -245,6 +245,18 @@  void error_vreport(const char *fmt, va_list ap)
 }
 
 /*
+ * Print an error message to current monitor if we have one, else to stderr.
+ * Format arguments like vsprintf().  The resulting message should be
+ * a single phrase, with no newline or trailing punctuation.
+ * Prepend the current location and append ": " strerror(errno) "\n".
+ * It's wrong to call this in a QMP monitor.  Use error_setg() there.
+ */
+void error_vreport_errno(const char *fmt, va_list ap)
+{
+    vreport(REPORT_TYPE_ERROR, errno, fmt, ap);
+}
+
+/*
  * Print a warning message to current monitor if we have one, else to stderr.
  * Format arguments like vsprintf().  The resulting message should be
  * a single phrase, with no newline or trailing punctuation.
@@ -286,6 +298,22 @@  void error_report(const char *fmt, ...)
 }
 
 /*
+ * Print an error message to current monitor if we have one, else to stderr.
+ * Format arguments like sprintf().  The resulting message should be
+ * a single phrase, with no newline or trailing punctuation.
+ * Prepend the current location and append ": " strerror(errno) "\n".
+ * It's wrong to call this in a QMP monitor.  Use error_setg() there.
+ */
+void error_report_errno(const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    vreport(REPORT_TYPE_ERROR, errno, fmt, ap);
+    va_end(ap);
+}
+
+/*
  * Print a warning message to current monitor if we have one, else to stderr.
  * Format arguments like sprintf(). The resulting message should be a
  * single phrase, with no newline or trailing punctuation.